Laryngoscopes are commonly used medical diagnostic instruments used to observe the throat area of a patient generally including a handle and a laryngeal blade which is removably attachable to the handle. The handle typically retains a power supply, such as a set of dry cell batteries, which energize a miniature lamp retained in an upper end of the handle. Light from the miniature lamp is directed to the end of the attached laryngeal blade in order to provide illumination and allow examination of the larynx. The laryngeal blade is constructed so as to push on the tongue during examination.
Instruments having light sources mounted in the upper end of the handle do not energize the light source until the laryngeal blade is attached. Typically, connection of the blade to the instrument handle draws the electrical contacts of the lamp assembly to the corresponding contacts of the power source.
In prior art devices, as described, it is possible for debris and body fluids to enter the blade and ultimately the hollow handle and the lamp assembly, thereby fouling the electrical contacts to the point in which premature replacement is required.
Certain prior art devices, such as those described in U.S. Pat. Nos. 4,669,449 and 4,694,822, each issued to Bauman, describe laryngoscopes having handles which are completely submersible. These devices have elaborate sealing means which include a tubular elastomeric body which is fitted in an upper portion of the handle, the body having additional provision for a pair of electrical terminals extending through the elastomeric body. Though these devices are quite useful, it is not always necessary to make the entire instrument handle fluid tight. On the other hand, it is highly desirous for the reasons stated above to protect the internal electrical contacts interconnecting the lamp assembly and the power source. Moreover, it is equally desirous to be able to maintain an effective seal regardless of whether or not the blade is actually attached to the handle.